This invention relates to an automated manufacturing of lamp tiles and electronic packaging units, more specifically, to manufacturing lamp tiles and electronic packaging units from a plurality of lead frame reels in an assembly line process.
Small light lamps such as light emitting diodes (LEDs) have been widely used as indicators or components of displays because of their high mechanical stability, low operating voltage, and long service life. When a plurality of the small light lamps are arranged in a two dimensional array and inserted into an electrically wired board configured to control each lamp, the resulting structure forms a large display board. In one prior system, such large display boards have been employed as score boards in sports arenas.
Manufacturing of display boards requires wiring of internal electrical circuit for controlling each lamp and wiring sockets for receiving each lamp. The lamps also must be individually inserted into the sockets. The preceding requirements, among others, make the manufacturing of display boards to be cumbersome and not readily adaptable to an automated assembly line processing. In turn, the display boards are ordinarily custom designed with high manufacturing costs.
Electronic packages are widely used to electrically connect electronic devices, such as semiconductor integrated circuits or microchips to bonding fingers of conductive leads to form the input/output leads for the package. It has become increasingly challenging to fabricate lead frames having closely spaced bonding fingers. As the number of input/output leads increases and as chip sizes shrink, the spacing between the leads decreases so that it is difficult to fabricate lead frames even using chemical etching techniques. The leads also must be located at specified distances from the electronic device and the spacing between the bonding fingers themselves is limited to the thickness of the lead frame material itself. The preceding requirements, among others, make the manufacturing of electronic packaging units to be cumbersome.
The present invention is directed to a method, system and apparatus for manufacturing electronic packaging units. These electronic packaging units are typically housings which are configured to receive electronic devices, such as microchips, semiconductors or light emitting diodes (LEDs). The electronic device is electrically connected to leads for supplying power or receiving electric signals.
Specifically, the present invention relates to a method for fabricating at least one electronic packaging unit having a molded body and a plurality of electrically conductive leads protruding therefrom, by providing a first lead frame segment defining a first aperture and including at least one first lead extending into the first lead frame aperture; providing a second lead frame segment defining a second aperture and including at least one second lead extending into the second lead frame aperture; overlaying the first and second lead frame segments above the other and positioning the first and second leads spaced apart from each other by a predetermined distance in a side view of the overlaid lead frame segments; and depositing molding material in a predetermined pattern on the first and second leads, thereby forming the molded body wherein a portion of the first lead and a portion of the second lead each protrude from the deposited molding material.
This method includes the steps of forming an opening over at least one lead for receiving an electronic device and trimming the first and second leads from the first and second lead frame segments. The step of overlaying the first and second leads includes the step of setting the predetermined distance to be between 0.01 and 0.03 inches, and preferably, between 0.01 and 0.015 inches.
Preferably, the first frames segment are produced by the step of stamping the first lead frame segments on a first elongated sheet made of electrically conductive rigid material, and the second frame segments are made by the step of stamping the second lead frame segments on a second elongated sheet made of electrically conductive rigid material.
The invention also relates to a system for fabricating a plurality of electronic packaging units, comprising a plurality of first lead frame segments which define first apertures and include a plurality of first leads extending into the first lead frame apertures; a plurality of second lead frame segments which define second apertures and including a plurality of second leads extending into the second lead frame apertures; a plurality of pins configured to overlay one of the first and second lead frame segments; a feeder for receiving the plurality of first and second lead frame segments and for overlaying the plurality of pins on one of the first and second lead frame segments such that a portion of each of corresponding said first and second leads are spaced apart from each other by a predetermined distance in a side view of the overlaid lead frame segments; and a molder configured to deposit molding material in a predetermined pattern such that a portion of each corresponding the first lead protrudes from the deposited molding material, and a portion of each corresponding the second lead protrudes from the deposited molding material.
The system preferably includes a trimmer configured to cut the first and second leads from the first and second lead frame segments, a first stamping device configured to stamp the first and second lead frame segments on first and second elongated sheets made of electrically conductive rigid material.
The present invention is also directed to an electronic packaging unit including a molded body formed from a mold material, a first lead including a first portion with the mold material deposited thereupon and extending within the molded body and a second portion that protrudes from the molded body; and a second lead spaced from the first lead, including a first portion with the mold material deposited thereupon and extending within the molded body and a second portion that protrudes from the molded body.
The packaging unit preferably has first and second leads that lie substantially in first and second planes and the first and second planes are parallel with respect to each other. One of the first and second leads can be disposed along a portion of a bottom of the molded body. The molded body preferably has a cavity and the cavity is configured to receive an electronic device. Preferably, a terrace is provided adjacent the cavity and at least one of the first and second leads is exposed along the terrace. The molded body can include a second terrace adjacent the cavity with one of the first and second leads is exposed along the second terrace.
The packaging unit preferably includes a first or second lead with a hole for receiving the mold material. The packaging unit can also include a third lead including a first portion with the mold material deposited thereupon and extending within the molded body and a second portion that protrudes from the molded body, and the first, second, and third leads are spaced from one another. Preferably, the first, second, and third leads are substantially planar and are disposed parallel with respect to each other.
The present invention is also directed to a method and apparatus for manufacturing lamp tiles. A lamp tile is a panel which has a plurality of light openings into which small light lamps are inserted and which includes a plurality of anode and cathode leads electrically connected to anode and cathode ends of corresponding small lamps for supplying or cutting off electrical power to the lamps. The lamp tiles are mounted into a display board configured to receive the anode and cathode leads of the lamp tiles. Such a display board also includes control circuit to control the on/off states of each lamp tile.